Metal shingles are considered desirable in many roofing installations due to their longevity and distinctive appearance. However, shingles made of bulk materials have inherent thickness not possessed by sheet metal. This thickness has made bulk shingles more desirable in some respects than conventional metal shingles. As used herein, the term xe2x80x9cbulk materialsxe2x80x9d refers to materials used in conventional shingles that have inherent thickness. The term xe2x80x9cbulk shinglesxe2x80x9d refers to shingles fabricated with bulk materials. Examples of bulk materials are ceramic tile, asphalt, wood shake, and foamed plastic.
Because bulk shingles are fabricated from material that is thicker than the sheet metal used in metal shingles, they have a higher thermal resistance than conventional metal shingles. In addition, bulk materials typically have higher thermal resistance per unit thickness than metal. It is known to include a sheet of bulk material (e.g., foamed plastic material) in the central planar portion of a metal shingle to improve its thermal resistance, effectively creating a bulk shingle. Such an arrangement is disclosed, for example, in U.S. Pat. No 5,442,888 to Ilnyckyj. However, there remains a need for a metal-shingle roofing system having improved insulation value without the requirement for additional materials.
The thickness of bulk shingles can impart a texture to the roofing system in which they are installed. When courses of bulk shingles are allowed to overlap, some shingles in the roofing system are raised with respect to others. Depending on the angle of light, the raised shingles can cast shadows on adjacent shingles. This shadowing and the textured pattern provided by raised and lowered shingles results in an appearance that many consider attractive.
The sheet of foamed plastic material disclosed in U.S. Pat. No. 5,442,888 to Ilnyckyj imparts an appearance of thickness to the shingle to which it is adhered. A roofing system using such a shingle may have some textured appearance. The need remains, however, for a metal shingle having an appearance of thickness without the requirement for its central planar portion to be given bulk thickness by the inclusion of additional materials. A further need remains for a roofing system having a textured appearance beyond that obtained by the conventional stacking of overlapping shingles.
A further need remains for a metal shingle that may be used in a radiused roofing system. Radiused roofing systems are used in conjunction with curved walls. Because courses of shingles cannot be laid out in straight lines in a radiused roofing system, conventional interconnected metal shingles are difficult to use in such a system.
The need also remains to provide ventilation under the surface of a metal roofing system. In conventional metal roofing systems that are installed in hot and sunny climates, for example, metal shingles convert sunlight into heat, which raises the temperature of the roof substrate and thus contributes to cooling inefficiency. It is particularly desirable to provide ventilation below the surface of a metal roofing system. In conventional roofing systems, ventilation is provided in the attic space beneath the roof substrate. A number of ventilation holes, referred to as xe2x80x9csoffit vents,xe2x80x9d are provided beneath the eaves of the roof. Cool air is drawn into the attic space to replace hot air, which exits the attic space through vents in the roof or sides of the structure supporting the roof. Although such an arrangement provides some exchange of air, additional ventilation would be desirable.
A roofing system according to various aspects of the present invention includes first and second pluralities of shingles. Each shingle includes a respective central planar portion. The shingles of each plurality are arranged such that their respective central planar portions are substantially co-planar. The first and second pluralities of shingles are arranged together such that: (1) each shingle of the first plurality is adjacent at least one shingle of the second plurality; and (2) the central planar portions of the shingles of the first plurality are displaced, with respect to the central planar portions of the shingles of the second plurality, by a separation distance. This displacement is along an axis perpendicular to the central planar portions of both pluralities of shingles. The separation distance is substantially greater than the thickness of the central planar portions of each shingle of both pluralities of shingles.
By displacing pluralities of adjacent shingles, such a roofing system provides a number of aesthetic and functional benefits. Such benefits include the availability of, inter alia, improved ventilation, textured appearance, and shadowing (under suitable lighting conditions).
A surfacing shingle according to various aspects of the present invention includes a central planar portion and several edge portions. The central planar portion has a first surface and a second surface opposite the first surface. The edge portions include: a first edge portion at a first edge of the central planar portion; a second edge portion at a second edge of the central planar portion; a third edge portion at a third edge of the central planar portion; and a fourth edge portion at a fourth edge of the central planar portion. The first, second, and third edge portions are each oriented at an acute angle with respect to the first surface. The fourth edge portion is oriented at an acute angle with respect to the second surface. The first and second edges of the central planar portion are opposite each other, as are the third and fourth edges.
Advantageously, such a shingle permits displacement by a separation distance that is substantially greater than the thickness of its central planar portion. Such a separation distance is highly significant because a roofing system using such shingles, according to aspects of the invention, may achieve a textured appearance and provide shadowing even when the central planar portions are free of bulk material. In addition, such shingles inherently provide a support structure for elevation of a surfacing structure from a substrate. The shingles thus cooperate to form an inherently supported surfacing structure in a ventilated roofing system according to further aspects of the invention.
By elevating a surfacing structure from a roofing substrate, thermal conductivity between the structure and substrate is reduced. Thus, thermal shock to a substrate from rapid heating and cooling of a surfacing structure (e.g., from changing levels of sunlight onto metallic shingles) is avoided.
A ventilated roofing system according to various aspects of the present invention includes a surfacing structure coupled to a roofing substrate. The surfacing structure, which may be comprised of interconnected shingles, is elevated with respect to the substrate such that an airspace is disposed between the substrate and the underside of the surfacing structure. The airspace is made accessible to both the first and second portions of the substrate. The system further includes a first ventilation port at the first portion of the substrate for coupling the airspace to the exterior of the roofing system; and a second ventilation port at the second portion of the substrate for coupling the airspace to the exterior of the roofing system.
Shingles may be installed onto a roofing substrate, according to a method of the invention, by (1) providing a plurality of like shingles, and (2) installing the plurality of shingles onto the substrate. Each shingle of the plurality includes a central planar portion that is fabricated of sheet material. Metal, particularly copper, is considered particularly advantageous for fabrication of the central planar portion. Each central planar portion has a respective first surface and a respective second surface opposite the first surface. The shingles are installed onto the substrate such that (1) a first shingle of the plurality is secured to the substrate with the first surface of its central planar portion facing upwards and away from the substrate; (2) a second shingle of the plurality is coupled to the first shingle, the second surface of the central planar portion of the second shingle facing upwards and away from the substrate; and (3) a third shingle of the plurality is coupled to the substrate and to the second shingle, the first surface of the central planar portion of the third shingle facing upwards and away from the substrate. The second shingle of the plurality may be coupled to the first and third shingles of the plurality prior to installation of the plurality of shingles onto the substrate.